Chickenpox

Two things here. Chickenpox can make children pretty miserable and isn't always a trivial thing. My DD had to be admitted to hospital when she had it. So bear in mind a poorly child may want to stay home, or not be up to doing much when they visit.

Second, the herpes family of viruses can do odd things. The chickenpox (varicella) virus does remain in minute traces in the nervous tissues to later re-appear as a form of herpes zoster or shingles. Shingles is a nasty illness which can cause severe nerve pain, as it attacks the tissues around certain nerves. This is why it only affects certain parts of the body, and not others.
Shingles is so painful and debilitiating that a vaccine is now recommended for anyone over 70, as we become more vulnerable to it as we age.
It is very important then that people who are immuno-compromised, or on high dose cortico-steroids, should keep away from any one who has chicken-pox.

You can't catch shingles from someone who has shingles or chickenpox, but you can get chickenpox from someone with shingles if you haven't had chickenpox before.

Isn't it complicated. My DD, who had chicken pox as an infant, got shingles aged 9. We were so surprised as we thought it was only for the elderly.

I don't think I have had either but perhaps I did as I didn't catch cp from any of my DC or DGC.

I had a shingles jag recently.

I would probably risk it if I were you, given that your DGS wants to see you and probably isn't very poorly. Up to you!